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Re: Validity

From: Johannes Koch <koch@w3development.de>
Date: Fri, 04 Nov 2005 09:58:20 +0100
Message-ID: <436B22AC.5080707@w3development.de>
To: w3c-wai-gl@w3.org

Gez Lemon wrote:
> The arguments put forwards against validity (from the
> face-to-face meeting in Seattle) can be summarised as:
> 1: Validity isn't essential for accessibility
> 2: Some developers think they're being clever creating accessible
> content, but they aren't
> 3: The people who wrote the specification don't really want anyone to
> be bothered by it
> 4: Legislation could result in people being prosecuted for invalid markup

Technically, conformance to specification is necessary for communication 
between information provider and consumer, and so is essential for 
consumers to be able to _access_ the information. Otherwise the consumer 
has to implement error recovery, heuristics, guesses, etc. Validity is 
one part of specification conformance. Another one (for markup) is this: 
Markup specifications use concepts like heading, list, table, etc. and 
define elements/attributes to transfer these concepts into markup code. 
If the information provider wants to use one of the concepts, he has to 
use the correct markup for this concept. OTOH, the information provider 
has to use specific markup only to describe concepts which the markup is 
intended for.

One exception may be additional code that may be necessary to overcome 
problems that the specification authors were not aware of and so is not 
part of the spcification. In the case of markup, user agents should not 
be confused by this, because they are required to ignore it and try to 
process the child nodes. I think it's similar with "extensions" to CSS, 
as long as the syntax conforms to the grammar.

Johannes Koch
In te domine speravi; non confundar in aeternum.
                             (Te Deum, 4th cent.)
Received on Friday, 4 November 2005 08:58:52 UTC

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